Used to be, in old Hollywood movies or cartoons, whenever some joke was made at the expense of an Asian character, or the scene switched to an Asian location (an actual Asian country or some generalized Chinatown), you would inevitably hear a little stacotto nine-note musical figure, like this, usually played on a xylophone:

Duh-duh-duh-duh duh duh, duh-duh duh!

It was the "universally stereotypically Chinese theme". For reference, it also appears in modified form in the chorus of the song "Kung Fu Fighting" and (somewhat oddly) at the beginning of the song "Turning Japanese". However, it doesn't really sound especially Chinese (to me, at least; I assume the intervals are thought to be somewhat non-western).

What the hell is this music, and how did it become a universal shorthand for any number of cultures?